Search Publications
Cassini UVIS observations of Europa's oxygen atmosphere and torus
Hendrix, A. R.; Shemansky, Donald E.; Hansen, Candice J.
Observations of the Europa environment using the Cassini UltraViolet Imaging Spectrograph (UVIS) show the presence of an extended atomic oxygen atmosphere in addition to the bound molecular oxygen atmosphere first detected by Hubble Space Telescope in 1994 [D.T. Hall, D.F. Strobel, P.D. Feldman, M.A. McGrath, H.A. Weaver, 1995, Detection of an oxy…
Ejection of nitrogen from Titan's atmosphere by magnetospheric ions and pick-up ions
Luhmann, J. G.; Johnson, R. E.; Leblanc, F. +3 more
A 3-D Monte Carlo model is used to describe the ejection of N and N 2 from Titan due to the interaction of Saturn's magnetospheric N + ions and molecular pick-up ions with its N 2 atmosphere. Based on estimates of the ion flux into Titan's corona, atmospheric sputtering is an important source of both atomic and mol…
The composition and size distribution of the dust in the coma of Comet Hale Bopp
Waters, L. B. F. M.; Dominik, C.; de Koter, A. +2 more
We discuss the composition and size distribution of the dust in the coma of Comet Hale-Bopp. We do this using a model fit for the infrared emission measured by the Infrared Space Observatory (ISO) and the measured degree of linear polarization of scattered light at various phase angles and wavelengths. The effects of particle shape on the modeled …
Diverse albedos of small trans-neptunian objects
Grundy, W. M.; Noll, K. S.; Stephens, D. C.
Discovery of trans-neptunian object (TNO) satellites and determination of their orbits has recently enabled estimation of the size and albedo of several small TNOs, extending the size range of objects having known size and albedo down into the sub-100 km range. In this paper we compute albedo and size estimates or limits for 20 TNOs, using a consi…
Dynamics of cloud features on Uranus
Sromovsky, L. A.; Fry, P. M.
Near-infrared adaptive optics imaging of Uranus by the Keck 2 telescope during 2003 and 2004 has revealed numerous discrete cloud features, 70 of which were used to extend the zonal wind profile of Uranus up to 60° N. We confirmed the presence of a north-south asymmetry in the circulation [Karkoschka, E., 1998. Science 280, 570-572], and improved …
Uranus in 2003: Zonal winds, banded structure, and discrete features
Hammel, H. B.; de Pater, I.; Gibbard, S. +2 more
Imaging of Uranus in 2003 with the Keck 10-m telescope reveals banded zonal structure and dozens of discrete cloud features at J and H bands; several features in the northern hemisphere are also detectable at K'. By tracking features over four days, we extend the zonal wind profile well into the northern hemisphere. We report the first measurement…
The cloud structure of the jovian atmosphere as seen by the Cassini/CIRS experiment
Flasar, F. Michael; Conrath, Barney J.; Gierasch, Peter J. +1 more
We analyze the thermal infrared spectra of Jupiter obtained by the Cassini-CIRS instrument during the 2000 flyby to infer temperature and cloud density in the jovian stratosphere and upper troposphere. We use an inversion technique to derive zonal mean vertical profiles of cloud absorption coefficient and optical thickness from a narrow spectral w…
Radar imaging of Saturn's rings
Nicholson, Philip D.; French, Richard G.; Campbell, Donald B. +4 more
We present delay-Doppler images of Saturn's rings based on radar observations made at Arecibo Observatory between 1999 and 2003, at a wavelength of 12.6 cm and at ring opening angles of 20.1°⩽|B|⩽26.7°. The average radar cross-section of the A ring is ∼77% relative to that of the B ring, while a stringent upper limit of 3% is placed on the cross-s…
Cassini UVIS observations of Jupiter's auroral variability
Dougherty, Michele K.; West, Robert A.; Gurnett, Donald A. +20 more
The Cassini spacecraft Ultraviolet Imaging Spectrograph (UVIS) obtained observations of Jupiter's auroral emissions in H 2 band systems and H Lyman- α from day 275 of 2000 (October 1), to day 81 of 2001 (March 22). Much of the globally integrated auroral variability measured with UVIS can be explained simply in terms of the rotation of …
Spectrophotometry of the small satellites of Saturn and their relationship to Iapetus, Phoebe, and Hyperion
Buratti, B. J.; Hicks, M. D.; Davies, A.
We have obtained broadband spectrophotometric observations of four of the recently discovered small satellites of Saturn (Gladman et al., 2001, Nature 412, 163-166). The new data enable an understanding of the provenance, composition, and interrelationships among these satellites and the other satellites of Saturn, particularly Iapetus, Phoebe, an…